Containers for lithography mask and method of use

Abstract

A container is provided for storing a lithographic printing mask. A first container section is formed of a sturdy material which defines a central inner recess area that is shaped to house a mask and to hold outer edges of a mask without touching a pattern on the mask. A second identical container section is placed against the first container section with a mask housed within recesses of both to form a container which has a common pressure level all around and therein. A higher pressure level is then applied outside the container causes the first and second sections of the container to be held together. To remove the mask from the container, the pressure outside the container is reduced to substantially the pressure level inside the container and the first and second sections are pulled apart.

What is claimed is:  
     
         1 . A container for housing a lithographic mask comprising: 
 a first section; and    a second section in contact with the first section with the contacting first and second sections defining a cavity having a size which is sufficient to house a lithographic mask and provide an air tight seal around the cavity when pressure within the cavity is less than pressure outside the container such that dust and other particles cannot reach a lithographic mask housed in the cavity.    
     
     
         2 . A container for storing a lithographic printing mask comprising: 
 a first container section formed of a sturdy material; and    a second container section formed of a sturdy material, wherein when the first and second container sections are placed together they define a cavity therein having a size to fixedly house a mask while not contacting a mask pattern on the mask and provide an air tight seal around the cavity when pressure within the cavity is less than pressure outside the container such that dust and other particles cannot reach the mask housed in the cavity.    
     
     
         3 . The container of  claim 2  further comprising a compressible material located on a surface of at least one of the first and second container sections where they come together and surrounding the cavity defined by the first and second container sections for providing the air tight seal.  
     
     
         4 . The container of  claim 3  wherein the compressible material is an O-ring.  
     
     
         5 . The container of  claim 3  wherein the compressible material is a layer of a compressible material.  
     
     
         6 . The container of  claim 2  wherein the first and second container sections are formed from a material from one of a group consisting of metal, plastic, and a sturdy composition material.  
     
     
         7 . The container of  claim 2  wherein a clean mask is placed in the cavity of a cleaned first container section in a clean vacuum chamber at a predetermined first pressure level, a cleaned second container section is aligned with the first container section and is placed in contact with the first container section, and the first pressure level in the vacuum chamber is raised to a second higher pressure level to seal and hold the sealed first and second container sections together.  
     
     
         8 . A container for storing a lithographic printing mask comprising: 
 a first container section formed of a sturdy material and defining a first cavity which is shaped for contacting an edge section of a mask to be stored in the container and covers, but does not contact an area of a mask pattern on the mask when the edge section of the mask is placed in the cavity;    a second container section formed from a sturdy material and defining a second cavity therein having a size which contacts an edge section of a mask to be stored in the container wherein when the first and second container sections are placed together they fixedly house the mask in the first and second cavities and provide an air tight seal around the cavity when pressure within the first and second cavities is less than pressure outside the container such that dust and other particles cannot reach the mask housed in the cavity.    
     
     
         9 . A container for storing a lithographic printing mask comprising: 
 a first container section formed of a sturdy material and defining a first cavity which is shaped for contacting an edge section of a mask to be stored in the container and covers, but does not contact an area of a mask pattern on the mask when the edge section of the mask is placed in the cavity;    a second container section formed from a sturdy material and defining a second cavity therein having a size which contacts an edge section of a mask to be stored in the container wherein when the first and second container sections are placed together they fixedly house the mask in the first and second cavities and provide an air tight seal around the cavity when pressure within the first and second cavities is less than pressure outside the container such that dust and other particles cannot reach the mask housed in the cavity.    
     
     
         10 . The container of  claim 9  further comprising a compressible material located on a surface of at least one of the first and second container sections where they come together and surrounding the first and second cavities defined by the first and second container sections, respectively, for providing the air tight seal.  
     
     
         11 . The container of  claim 10  wherein the compressible material is an O-ring.  
     
     
         12 . The container of  claim 9  wherein the compressible material is a thin layer of a compressible material.  
     
     
         13 . The container of  claim 9  wherein the first and second container sections are formed from a material selected from a group consisting of metal, plastic, and a sturdy composition material.  
     
     
         14 . The container of  claim 9  wherein a clean mask is placed in the cavity of a cleaned first container section in a clean vacuum chamber at a predetermined first pressure level, a cleaned second container section is aligned with the first container section and is placed in contact with the first container section, and the first pressure level in the vacuum chamber is raised to second higher pressure level to seal and hold the sealed first and second container sections together.  
     
     
         15 . A method of storing a mask in a container comprising first and second sections which are both cleaned to remove particles thereon, the method comprising the steps of: 
 placing first and second cleaned sections of the container and a cleaned mask in a chamber and reducing the pressure within the chamber to a first pressure level;    while the mask is in the chamber which is at the first pressure level, placing the mask in a cavity defined by portions of the first container section such that a mask pattern on the mask does not contact any portion of the first container;    while the mask is in the cavity, placing the second container section in contact with the first container section to form the container and to seal the cavity therein from dust and particles and any pressure changes outside the container; and    raising the first pressure level surrounding the container to a second higher pressure level to seal and hold the first and second container sections together.    
     
     
         16 . The method of  claim 15  wherein a compressible material is located on a surface of at least one of the first and second container sections where they come together and surrounds the cavity defined by the first and second container sections for providing the air tight seal.  
     
     
         17 . The method of  claim 16  wherein the compressible material is an O-ring.  
     
     
         18 . The method of  claim 16  wherein the compressible material is a thin layer of a compressible material.  
     
     
         19 . The method of  claim 15  wherein the first and second container sections are formed from a material selected from a group consisting of metal, plastic, and any sturdy composition material.  
     
     
         20 . The method of  claim 15  wherein the first pressure level is below normal atmospheric pressure and the second pressure level is atmospheric pressure.